Now, we know what tone is as a literary device. It is quite often confused with mood. Mood is what the reader and/or audience experience from a piece of writing while tone is what the author wishes to communicate.
So, typically, the author's tone and the reader's mood imbibed from the text are the same. This is when the author's tone is received as the mood by audiences or readers. This needn't always be the case. The author's tone need not be the mood the reader or audience feels.
It is the tone that induces the mood in the reader or audience. Imagine an actor performing to a writer's script. Let us take Shakespeare's plays as an example. Plays from the sixteenth and seventeenth centuries are performed by theatre groups all over the world, even today. And no two productions would be the same. What did Shakespeare intend? We do not yet know, despite research scholars working relentlessly to determine that. Therefore, the tone set by the author needn't be the mood affected by the tone.